Tunable room-temperature ferromagnetism in Co-doped two-dimensional van der Waals ZnO.
Tunable room-temperature ferromagnetism in Co-doped two-dimensional van der Waals ZnO.
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共掺杂二维范德华氧化锌中的可调谐室温铁磁性
DOI：
10.1038/s41467-021-24247-w
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发表时间：
2021-06-25
影响因子：
16.6
通讯作者：
Yao J
中科院分区：
文献类型：
--
作者：
Chen R;Luo F;Liu Y;Song Y;Dong Y;Wu S;Cao J;Yang F;N'Diaye A;Shafer P;Liu Y;Lou S;Huang J;Chen X;Fang Z;Wang Q;Jin D;Cheng R;Yuan H;Birgeneau RJ;Yao J
最近在二维货车德瓦耳斯晶体中发现的铁磁性引起了人们对探索降维基本自旋相互作用的兴趣。然而，现有的材料候选人有几个限制，特别是缺乏内在的室温铁磁秩序和空气稳定性。在这里，由于在大量稀释的磁性氧化物中观察到的极高的居里温度，我们证明了Co掺杂的石墨烯样氧化锌（一种在空气中化学稳定的层状材料）中的室温铁磁性，直到单原子厚度。通过磁光克尔效应、超导量子干涉仪和X射线磁圆二色性测量，我们观察到了这种奇异材料系统在室温及以上温度下的自发磁化的明显证据。透射电子显微镜和原子力显微镜的结果明确排除金属钴或钴氧化物簇的存在。X射线衍射分析表明，在ZnO的石墨晶格中，Co原子以Co ~（2+）的形式存在。通过改变Co掺杂水平，我们观察到由于杂质带交换和超交换相互作用之间的相互作用，顺磁性，铁磁性和较不有序的相之间的转变。我们的发现开辟了另一条在室温下实现2D铁磁性的道路，具有卓越的可调谐性和鲁棒性。货车德瓦耳斯磁性材料（vdW）已经允许探索磁性的二维极限，然而，大多数vdW仅在低温下是磁性的。在此，作者克服了这一限制，观察钴掺杂的石墨烯类氧化锌中的室温磁有序。
The recent discovery of ferromagnetism in two-dimensional van der Waals crystals has provoked a surge of interest in the exploration of fundamental spin interaction in reduced dimensions. However, existing material candidates have several limitations, notably lacking intrinsic room-temperature ferromagnetic order and air stability. Here, motivated by the anomalously high Curie temperature observed in bulk diluted magnetic oxides, we demonstrate room-temperature ferromagnetism in Co-doped graphene-like Zinc Oxide, a chemically stable layered material in air, down to single atom thickness. Through the magneto-optic Kerr effect, superconducting quantum interference device and X-ray magnetic circular dichroism measurements, we observe clear evidences of spontaneous magnetization in such exotic material systems at room temperature and above. Transmission electron microscopy and atomic force microscopy results explicitly exclude the existence of metallic Co or cobalt oxides clusters. X-ray characterizations reveal that the substitutional Co atoms form Co2+ states in the graphitic lattice of ZnO. By varying the Co doping level, we observe transitions between paramagnetic, ferromagnetic and less ordered phases due to the interplay between impurity-band-exchange and super-exchange interactions. Our discovery opens another path to 2D ferromagnetism at room temperature with the advantage of exceptional tunability and robustness. Van der Waals magnetic materials (vdWs) have allowed for the exploration of the two dimensional limit of magnetism, however, most vdWs are only magnetic at low temperature. Herein, the authors overcome this limitation, observing room temperature magnetic ordering in Cobalt doped graphene-like Zinc-Oxide.
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影响因子：
38.3
作者：
Huang, Bevin;Clark, Genevieve;Xu, Xiaodong
通讯作者：
Xu, Xiaodong
影响因子：
56.9
作者：
Klein, D. R.;MacNeill, D.;Jarillo-Herrero, P.
通讯作者：
Jarillo-Herrero, P.
影响因子：
10.8
作者：
Alghamdi, Mohammed;Lohmann, Mark;Shi, Jing
通讯作者：
Shi, Jing
影响因子：
8.6
作者：
Shinde, SR;Ogale, SB;Venkatesan, T
通讯作者：
Venkatesan, T
影响因子：
10.8
作者：
Li, Qian;Yang, Mengmeng;Qiu, Ziqiang
通讯作者：
Qiu, Ziqiang